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</a></div> <!----></nav>  <ul class="sidebar-links"><li><a href="/docs/node/" aria-current="page" class="sidebar-link">介绍</a></li><li><section class="sidebar-group depth-0"><p class="sidebar-heading open"><span>Node.js 基础</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/docs/node/technology-architecture.html" aria-current="page" class="active sidebar-link">Node.js 技术架构</a></li><li><a href="/docs/node/fs-file.html" class="sidebar-link">文件模块</a></li><li><a href="/docs/node/static-server.html" class="sidebar-link">静态服务器</a></li><li><a href="/docs/node/fanyi.html" class="sidebar-link">命令行翻译工具</a></li><li><a href="/docs/node/operational-database.html" class="sidebar-link">操作数据库</a></li></ul></section></li></ul> </div></div><div class="el-scrollbar__bar is-horizontal"><div class="el-scrollbar__thumb" style="width:0;transform:translateX(0%);ms-transform:translateX(0%);webkit-transform:translateX(0%);"></div></div><div class="el-scrollbar__bar is-vertical"><div class="el-scrollbar__thumb" style="height:0;transform:translateY(0%);ms-transform:translateY(0%);webkit-transform:translateY(0%);"></div></div></div></aside> <main class="page"> <div class="re-page-top"><h1 class="title"><span>Node.js 技术架构</span></h1> <div class="re-page-index"><div class="page-index-title"><span class="open-catalog"><svg aria-hidden="true" class="icon arrow-right"><use xlink:href="#icon-bold-right"></use></svg> <span class="text">目录</span></span></div> <div class="page-index-content"><div class="page-catalog" style="display:none;"><div class="synopsis-wrap"><ul class="synopsis-ul"><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#api-文档" class="synopsis-link">API 文档</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#node-js-是什么" class="synopsis-link">Node.js 是什么</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#node-js-不是什么" class="synopsis-link">Node.js 不是什么</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#node-js-技术架构" class="synopsis-link">Node.js 技术架构</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#什么是-bindings" class="synopsis-link">什么是 bindings</a><ul class="synopsis-ul"><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#背景" class="synopsis-link">背景</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#bindings" class="synopsis-link">bindings</a></li></ul></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#js-与-c-交互案例" class="synopsis-link">JS 与 C++ 交互案例</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#什么是-eventloop" class="synopsis-link">什么是 EventLoop</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#node-js-工作流程" class="synopsis-link">Node.js 工作流程</a></li><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#面试题" class="synopsis-link">面试题</a><ul class="synopsis-ul"><li class="synopsis-li"><a href="/docs/node/technology-architecture.html#_1-下面的代码中-那个函数先执行" class="synopsis-link">1. 下面的代码中，那个函数先执行</a></li></ul></li></ul></div></div></div></div></div> <div class="theme-default-content content__default"><h2 id="api-文档"><a href="#api-文档" class="header-anchor">#</a> API 文档</h2> <ul><li>官方地址：<a href="http://nodejs.cn/api/" target="_blank" rel="noopener noreferrer">中文文档<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a>/<a href="https://nodejs.org/api/" target="_blank" rel="noopener noreferrer">英文文档<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li><a href="https://devdocs.io/" target="_blank" rel="noopener noreferrer">devdocs.io<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a> 搜索功能便捷，支持夜间模式，并且可以离线观看</li></ul> <h2 id="node-js-是什么"><a href="#node-js-是什么" class="header-anchor">#</a> Node.js 是什么</h2> <ul><li><p><strong>是一个平台</strong></p> <ul><li>让多种技术组合起来</li> <li>让 JavaScript 也能调用系统接口、开发后端应用</li></ul></li> <li><p><strong>Node.js 用到了哪些技术</strong></p> <ul><li>V8引擎</li> <li>libuv</li> <li>C/C++ 实现的 c-ares、http-parser、OpenSSL、zlib 等库</li></ul></li></ul> <h2 id="node-js-不是什么"><a href="#node-js-不是什么" class="header-anchor">#</a> Node.js 不是什么</h2> <ul><li><p><strong>不是 web 框架</strong></p> <ul><li>Node.js 并不是 web 后端框架</li> <li>所以你不能把 Node.js 与 Flask 或 Spring 对比</li></ul></li> <li><p><strong>不是编程语言</strong></p> <ul><li>Node.js 并不是后端的 JS</li> <li>所以你不能把 Node.js 与 Python 或 PHP 对比</li></ul></li></ul> <h2 id="node-js-技术架构"><a href="#node-js-技术架构" class="header-anchor">#</a> Node.js 技术架构</h2> <div class="flexible-container"><ul class="flexible-table"><li><p class="flexible-table__title"><b>Node.js API</b></p> <p>http 模块、fs 模块、stream 模块</p></li></ul> <ul class="flexible-table"><li><p class="flexible-table__title"><b>Node.js bindings</b></p> <p>让 JS 和 C/C++ 通信</p></li> <li><p class="flexible-table__title"><b>C/C++ 插件</b></p> <p>自定义其他能力</p></li></ul> <ul class="flexible-table"><li><p>JS 引擎</p> <p>V8</p></li> <li><p>跨平台异步I/O能力</p> <p>libuv</p></li> <li><p>DNS 解析</p> <p>c-ares</p></li> <li><p>加密解密</p> <p>OpenSSL</p></li> <li><p>其他...</p> <p>http_parser、zlib</p></li></ul></div> <p>随着 Node.js 的版本已经从 0.8 升级到 12.11.1，其架构也在一直变化中。如果你想看源码，推荐看 <a href="https://github.com/nodejs/node/tree/v0.10.0" target="_blank" rel="noopener noreferrer">Node.js v0.10.0<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a> 版本，因为这个版本使用了很久，而且源码相对最新版较少。</p> <p>如果想要了解更多，可以看 <a href="https://github.com/yjhjstz/deep-into-node" target="_blank" rel="noopener noreferrer">深入理解Node.js：核心思想与源码分析<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></p> <h2 id="什么是-bindings"><a href="#什么是-bindings" class="header-anchor">#</a> 什么是 bindings</h2> <h3 id="背景"><a href="#背景" class="header-anchor">#</a> 背景</h3> <ul><li>C/C++ 实现了一个 http_parser 库， 很高效</li> <li>你只会写 JS，但想使用这个库</li> <li>直接调用肯定不会成功，于是就需要一个中间的桥梁</li></ul> <h3 id="bindings"><a href="#bindings" class="header-anchor">#</a> bindings</h3> <ul><li>Node.js 用 C++ 对 <code>http_parser</code> 进行封装，使它符合某些要求，封装的文件名就叫做 <code>http_parser_bindings.cpp</code></li> <li>用 Node.js 提供的编译工具将其编译为 <code>.node</code> 文件，JS 代码就可以直接 require 这个 <code>.node</code> 文件</li> <li>这样 JS 就能调用 C++ 库，中间的桥梁就是 binding</li> <li>由于 Node.js 提供了很多 binding，所以要加个 s，这就是 <strong><code>bindings</code></strong> 的由来</li></ul> <h2 id="js-与-c-交互案例"><a href="#js-与-c-交互案例" class="header-anchor">#</a> JS 与 C++ 交互案例</h2> <ul><li>JS 调用 C++ 代码：<a href="http://nodejs.cn/api/addons.html#addons_function_arguments" target="_blank" rel="noopener noreferrer">官方示例<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li> <li>C++ 调用 JS 代码：<a href="http://nodejs.cn/api/addons.html#addons_callbacks" target="_blank" rel="noopener noreferrer">官方示例<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></li></ul> <h2 id="什么是-eventloop"><a href="#什么是-eventloop" class="header-anchor">#</a> 什么是 EventLoop</h2> <p><strong>Event 表示事件</strong>，如：</p> <ul><li>计时器到期，要执行一个事件</li> <li>文件读取完毕或出错，要执行一个事件</li> <li>socket 有内容了，关闭了，要执行一个事件</li></ul> <p><strong>Loop 就是循环</strong>，如：</p> <ul><li>wihile(true) 循环（死循环）</li> <li>Node.js 需要按照顺序轮询每种事件，这种事件往往都是循环，所以叫 loop</li></ul> <p><strong>EventLoop</strong></p> <ul><li>操作系统触发事件，JS 处理事件，EventLoop 就是对事件处理顺序的管理</li> <li>通常 EventLoop 会停留在 poll 阶段，不停的问操作系统，接下来有没有事情做</li></ul> <p>执行顺序图示</p> <img src="/docs/images/eventloop-process.jpg" alt="foo" style="width:500px;"> <h2 id="node-js-工作流程"><a href="#node-js-工作流程" class="header-anchor">#</a> Node.js 工作流程</h2> <img src="/docs/images/nodejs-process.jpg" alt="foo"> <h2 id="面试题"><a href="#面试题" class="header-anchor">#</a> 面试题</h2> <h3 id="_1-下面的代码中-那个函数先执行"><a href="#_1-下面的代码中-那个函数先执行" class="header-anchor">#</a> 1. 下面的代码中，那个函数先执行</h3> <div class="language-js extra-class"><pre class="language-js"><code><span class="token function">setTimeout</span><span class="token punctuation">(</span>f1<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span>
<span class="token function">setImmediate</span><span class="token punctuation">(</span>f2<span class="token punctuation">)</span>
</code></pre></div><p>一般情况下都是 <code>setImmediate(f2)</code> 先执行，因为它处在 check 阶段，只有在 Node.js 第一次运行时，会先进入 timers 阶段</p> <p>end 。。。</p></div> <footer class="page-edit"><!----> <div class="last-updated"><span class="prefix">上次更新：</span><span class="time">2021-03-21 17:15</span></div></footer> <div class="page-nav"><p class="inner"><span class="prev"><svg aria-hidden="true" class="icon"><use xlink:href="#icon-left"></use></svg> <a href="/docs/node/" class="prev router-link-active">介绍</a></span> <span class="next"><a href="/docs/node/fs-file.html">文件模块</a> <svg aria-hidden="true" class="icon"><use xlink:href="#icon-right"></use></svg></span></p></div> </main></div><div class="global-ui"><!----><!----></div></div>
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